Concrete or cement mixer trucks generally include a cab and a rotatable drum behind the cab that contains and mixes concrete materials. Such trucks typically include a single set of forward steering wheels and a plurality of rear, load supporting drive axles mounted on an elongated chassis which supports the cab and the drum.
Most federal, state and local highways and bridges have load limits which limit the overall vehicle weight, the weight per axle and the spacing of the axles. Auxiliary axles may be used to provide additional load-bearing wheels which can be lifted from the road surface when the additional wheels are not needed.
One type of auxiliary axle used with cement mixer trucks is generally referred to as a "tag axle" which is a separate high lift axle assembly pivotally mounted to the rear of the truck chassis. Tag axles generally include a mechanism for lowering the assembly so that the wheels may engage the road surface behind the truck to significantly increase the legal load carrying capacity of the truck. The increased load carrying capacity is effected not only by the fact that the load is spread over more axles, but also because the distance between the front and rearmost axles is significantly increased.
Tag axles generally are raised and lowered by means of a hydraulic system which can lower the tag axle to the road surface to share the load with the steering and drive wheels, and which can raise the tag axle up and out of the way to transport relatively light loads, to improve off-road maneuverability and/or to discharge material from the cement mixer. Further information regarding cement mixers and tag axle assemblies may be found, for example, in U.S. Pat. No. 5,498,021.
After material is discharged from the mixer, a problem remains regarding how to clean the equipment, such as a chute extending from the truck, used to deliver the material from the truck. The general practice is to wash off the equipment onto the ground. This leaves an undesirable and wasteful deposit of cement and/or other concrete materials at a construction or job site.